1. Field of the Invention
The present invention relates to a mechanical object size grader and specifically to a food grader for delicate foods.
2. Description of Related Art
The human population of the world has been in a continual state of growth during recent centuries. This growth has produced a substantial demand for the mass production of high-quality foods. In order to meet these pressing demands food processing equipment and machinery has been developed. Specialized machinery has been developed to size or sort damage-sensitive food products based on diameter.
It was discovered that rollers 14 with smooth surfaces would not move objects 86 across the rollers 14 for grading, regardless of the number or depth of the flats 22. When the flats 22 are cut, the areas in between the flats 22 are left in the original rounded shape and denoted as crowns 24. Crowns 24, the rounded portions of the roller 14, must exist to allow objects to float on the surface of the roller 14. In 1994, a roller bed for separating fines and slivers was designed to process foods, in particular French-fried potatoes, having fines and slivers in U.S. Pat. No. 5,279,427 (hereinafter U.S. Pat. No. '427). In U.S. Pat. No. '427, the flat portions 2 of the rollers did not have a roughened surface; the crown portions 4 of the rollers 14 had a roughened surface. As shown in FIG. 1, the surface of the roller 10 was first sandblasted and second was cut into 6 flats 2 parallel to the length of the roller 14. Therefore, the roller is made with the flats 2 having a smooth surface and the crowns 4 having a roughened surface.
In U.S. Pat. No. '427 the rollers operated at the same speed and had six flats and crowns that allowed a camming action to facilitate the falling of potato slivers in between the rollers. However, the camming action of the food processor in U.S. Pat. No. '427 caused damage to delicate foods such as green beans.
The rollers in U.S. Pat. No. '427 were constructed by starting with a 4-inch schedule 40-gauge stainless steel pipe 10 (FIG. 1). The pipe had several horizontal cuts or flats 2 made continuously over the length of the pipe. In U.S. Pat. No. '427, 6 flats 2 were cut to a depth of 0.90 inches with a 60-degree angle 8 between the flats leaving crowns 4 (FIG. 1).
To cause less damage to foods and other objects, the rollers need less of the camming action of U.S. Pat. No. '427. Camming can be reduced in direct proportion to increasing the number of flats 2 and decreasing the depth of the individual flats.
Another facet of the food sorting industry was machinery for sorting beans. A bean grader was designed having a grader drum with fixed grader bars, which extended between two angular end plates in U.S. Pat. No. 5,322,103 (hereinafter U.S. Pat. No. '103). The bean grader had a complex design and was difficult to manufacture and to maintain.
A product size food grading system was designed with a progressive speed system using thin plastic disks and flexible rubber pockets connected to rotary shafts in U.S. Pat. No. 5,558,234 (hereinafter U.S. Pat. No. '234). The food grading system in U.S. Pat. No. '234 was designed to eliminate the need for a vibratory sizer, reduce noise, occupy less floor space, waste less properly-sized product. The system in U.S. Pat. No. '234 is a different class of food processing equipment.
The present invention is an adjustable object size grader that grades objects based on diameter and will grade foods with at least 10 to 15 percent less product damage than any other related art; the adjustable object size grader is easy to maintain. Grading foods with less damage and ease of maintenance result in remarkable savings to the user.